What Treatments Need to Be Strengthened for GRC Decorative Panels in Humid Environments?

In humid environments (such as coastal areas, high-humidity inland regions, and areas with year-round rainfall), GRC decorative panels require systematic reinforcement to withstand long-term erosion from moisture and salt spray. The core approach is to build a three-in-one defense system of "impervious material substrate, hydrophobic surface protection, and enhanced structural drainage." The GRC solutions provided by Qinglong Group for the Hainan International Convention and Exhibition Center and several coastal hotel projects in Sanya are based on this very concept, remaining intact and as good as new after years of exposure to high-salt, high-humidity conditions.

Impermeability of the material substrate is fundamental to moisture protection. High-density GRC formulations with a low water-binder ratio (typically <0.3) must be used to reduce capillary porosity at the source and minimize channels for moisture ingress. For GRC designed for humid environments, Qinglong incorporates active admixtures such as silica fume and slag to further optimize the pore structure, keeping the 28-day water absorption rate below 8%. At the same time, the protective cover thickness (typically ≥15mm) must be strictly maintained to ensure the glass fiber mesh layers are fully encapsulated, preventing corrosion failure caused by carbonation or chloride ion penetration.

Hydrophobic surface protection is the first barrier against moisture contact. After GRC panels are installed and fully dried, all exposed surfaces must be coated with a high-quality penetrating silicone water repellent. This type of protective agent penetrates several millimeters into the capillary pores of the concrete, creating a one-way breathing "lotus effect" that prevents liquid water from penetrating while allowing internal water vapor to escape. Qinglong recommends applying two coats by brush or spray in humid regions to ensure even coverage, with particular attention to joints, internal and external corners, and other water-prone areas.

Structural drainage design is key to avoiding localized water accumulation. In the design of GRC curtain wall systems, a complete drainage path must be established. All horizontal or inclined component surfaces should be designed with a drainage slope of no less than 3%, and drip edges should be provided to prevent rainwater from flowing back. The cavity behind panel joints must be kept well ventilated to avoid moisture accumulation. For GRC components close to the ground or roof, a moisture-proof isolation layer should be provided.

Joint sealing and anti-corrosion of metal parts are important supplementary measures. All panel joints must be reliably sealed with high-elasticity, aging-resistant silicone sealant. All connecting metal fixtures and anchors must be made of 316 stainless steel or treated with heavy-duty anti-corrosion methods such as hot-dip galvanizing. Through the above systematic reinforcement treatments, GRC decorative panels are fully capable of withstanding the long-term test of all kinds of humid environments.